Prosimian primates are a highly diverse group, with three extant radiations: the lemurs of Madagascar, the lorises of Africa and Asia, and the Asian tarsiers. Milk composition has been investigated for a small subset of prosimian species: 7 Lemur species and 5 lorises. The general pattern that emerges from this limited data set is that the lemurs produce dilute, low-energy milks and the lorises produce milks with the highest fat and protein concentrations, and hence gross energy (GE) content, among primates. Varecia may be an exception, producing milks of higher GE, and especially higher protein concentration, than other Lemur species that have been studied. Eulemur and Lemur species produce dilute, low energy milks with little variation across lactation, among individuals within species, or even among species. This is one of a suite of traits that minimize daily energy expenditure among reproductive females. The higher energy milks from the loris species are also relatively similar among species. The pattern of maternal care may be an explanatory variable for the differences between lorises and lemurs, and the similarities within these groups. Lorises park their infants in nests while foraging, and return episodically to nurse them. In general, the lemurs carry their infants with them, and are more likely to fit the “nurse-on-demand” model. Varecia is a parker, possibly providing the “exception that proves the rule”.